JP2010003882A - Edge emitting semiconductor laser device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an edge emitting semiconductor laser device which is so configured and structured as to suppress crystal deterioration in a region of an active layer away from a light emission end face. <P>SOLUTION: The edge emitting semiconductor laser device has a multilayer structure wherein a first compound semiconductor layer 21, an active layer 23, and a second compound semiconductor layer 22 are stacked in order, and has a light emitting portion 20 which emits laser light from the light emission end face. The second compound semiconductor layer 22 has a current injection region 31 formed in a stripe geometry. In the second compound semiconductor layer 22, recesses 33 are formed in regions on both sides of the current injection region 31, being away from the current injection region 31 and also away from the light emission end face. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an edge-emitting semiconductor laser device.

  Edge-emitting semiconductor laser elements having a ridge structure or a double ridge structure are well known. In these edge-emitting semiconductor laser elements, the first compound semiconductor layer 21, the active layer 23, and the second compound semiconductor layer 22 are sequentially formed of a laminated structure, and laser light is emitted from the light emitting end face. It has the light emission part 20 to radiate | emit. The second compound semiconductor layer 22 is provided with stripe-shaped current injection regions 31. A schematic partial cross-sectional view of a conventional edge-emitting semiconductor laser device having such a structure having a double ridge structure is a schematic cross-sectional view of the edge-emitting semiconductor laser device of Example 1 shown in FIG. It is the same as a typical partial sectional view.

  By the way, in the semiconductor laser device for next-generation DVD, the edge-emitting semiconductor laser device must be operated at a high output. Therefore, lowering the drive current threshold, increasing the slope efficiency, improving the temperature characteristics, improving the noise characteristics, and improving the resistance to instantaneous optical damage (COD: Catastrophic Optical Damage) are important issues (for example, “ "Wide-gap semiconductor optical and electronic devices", edited by Fumio Hasegawa, published by Morikita Publishing).

  In particular, in order to improve the COD resistance, it is possible to reduce the light density at the light exit end face. For this reason, measures are taken such as reducing light confinement or reducing the light reflectivity at the light exit end face. . As a result, a nitride compound semiconductor laser element with an output of 170 mW has been commercialized. Alternatively, for the purpose of improving COD resistance, a mesa structure portion is provided, and an electrically connected electrode film is provided on the upper surface of the mesa structure portion, and the electrode film has tensile strain and is located on the side of the mesa structure portion. Japanese Laid-Open Patent Publication No. 2003-283039 discloses a semiconductor laser element that is formed so as to extend in the direction and is formed on a portion of an electrode film that extends laterally from a mesa structure and is formed with a strain suppression film that has a compressive stress. is there.

JP 2003-283039 A "Wide Gap Semiconductor Optical / Electronic Device", edited by Fumio Hasegawa, published by Morikita Publishing

  In the next-generation DVD, there is a strong demand for multilayering to further improve recording speed and to cope with higher recording density. For this reason, edge-emitting semiconductor laser devices also have higher output. Is required.

  By the way, when the high-power aging test is performed on the edge-emitting semiconductor laser device, it has been found by the inventor's examination that a phenomenon occurs in which the light output suddenly deteriorates in about 10 to 100 hours from the start of the aging test. I have done it. As a result of analysis of such a deterioration phenomenon, crystal deterioration has occurred in the active layer region located about 0.2 mm inward from the light emitting end face of the edge emitting semiconductor laser element. It became clear. This crystal deterioration is caused by melting of the compound semiconductor constituting the active layer, and a kind of void is generated in the region of the active layer. However, since such crystal degradation occurs at a position away from the light emitting end face, it cannot be solved by the technology for improving the COD resistance.

  Accordingly, an object of the present invention is to provide an edge-emitting semiconductor laser device having a configuration and structure capable of suppressing crystal deterioration in an active layer region remote from a light emitting end face.

In order to achieve the above object, an edge-emitting semiconductor laser device of the present invention comprises:
The first compound semiconductor layer, the active layer, and the second compound semiconductor layer are each composed of a laminated structure that is sequentially laminated, and has a light emitting portion that emits laser light from a light emission end face.
The second compound semiconductor layer has a stripe-shaped current injection region, and
The second compound semiconductor layer has recesses on both sides of the current injection region, spaced from the current injection region, and away from the light emitting end surface.

In the edge-emitting semiconductor laser device of the present invention, the light emitting portion may have a ridge structure. That is, in the edge-emitting semiconductor laser device of the present invention,
The second compound semiconductor layer has a lower layer portion and an upper layer portion protruding from the lower layer portion,
The upper layer portion of the second compound semiconductor layer corresponds to the current injection region,
A recessed part can be set as the structure provided in the lower layer part of the 2nd compound semiconductor layer.

Alternatively, in the edge-emitting semiconductor laser device of the present invention, the light emitting part may have a double ridge structure. That is, in the edge-emitting semiconductor laser device of the present invention,
The second compound semiconductor layer has a lower layer portion and three upper layer portions protruding from the lower layer portion,
The second upper layer portion of the second compound semiconductor layer located in the center corresponds to the current injection region,
The concave portion is a portion of the lower layer portion of the second compound semiconductor layer located between the first upper layer portion of the second compound semiconductor layer located on one edge and the second upper layer portion of the second compound semiconductor layer, And provided in the lower layer portion of the second compound semiconductor layer located between the third upper layer portion of the second compound semiconductor layer located at the other edge and the second upper layer portion of the second compound semiconductor layer. It can be set as the structure currently provided.

In the edge-emitting semiconductor laser device of the present invention including the preferred configuration described above, it is desirable that the recess be included in a region 0.2 mm away from the light emitting end face. That is, DS ₁ (unit: mm) is the distance from the light exit end surface to one end of the recess (the end of the recess located near the light exit end surface), and the other end of the recess (far from the light exit end surface). When the distance to the end of the recess located in the place is DS ₂ (unit: mm),
0.001 ≦ DS ₁ <0.2
0.2 <DS ₂
Is satisfied.

  In some cases, the second compound semiconductor layer has a lower layer portion and an upper layer portion, and the upper layer portion may be composed of a current injection region and a region for constricting current provided on both sides of the current injection region. it can. In this case, a recess is provided in a region where current is confined. Here, the region for confining the current can be obtained, for example, by implanting boron ions, hydrogen ions, or aluminum ions and making the ion-implanted region a high resistance region or an insulating region.

Furthermore, in the edge-emitting semiconductor laser device of the present invention including the preferred configuration, forms described above, (a Lg = DS ₂ -DS _2, the unit is m) length of the recess,
1 × 10 ⁻⁶ ≦ Lg
Preferably,
1 × 10 ⁻⁵ ≦ Lg ≦ 8 × 10 ⁻⁵
It is desirable to satisfy

Further, when the average width of the recess is W, the average distance from the current injection region to the recess (unit: mm) is DS ₃ , and the length of the active layer is L _Act , it is not limited,
0.001 ≦ DS ₃ ≦ 0.05
Preferably,
0.001 ≦ DS ₃ ≦ 0.02
Satisfied, also
1.25 × 10 ⁻² ≦ Lg / L _Act ≦ 2 × 10 ⁻¹
Preferably,
1.25 × 10 ⁻² ≦ Lg / L _Act ≦ 1 × 10 ⁻¹
It is desirable to satisfy The recess may be provided in the second compound semiconductor layer, may penetrate through the second compound semiconductor layer and reach the active layer, or may further reach the first compound semiconductor layer. Alternatively, or alternatively, the first compound semiconductor layer may be penetrated. Examples of the depth of the recess include 0.3 μm to 2.5 μm.

  In the edge-emitting semiconductor laser device of the present invention including the above preferred embodiments and configurations (hereinafter, these may be collectively referred to simply as “the present invention”), the configurations and structures of the light emitting portion and the laminated structure As such, it can have a well-known configuration and structure, and there is no particular limitation or limitation. The first compound semiconductor layer may be an n-type compound semiconductor layer, the second compound semiconductor layer may be a p-type compound semiconductor layer, the first compound semiconductor layer may be a p-type compound semiconductor layer, and the second compound semiconductor layer may be an n-type It is good also as a compound semiconductor layer.

  In the present invention, the edge-emitting semiconductor laser device is first provided on a substrate, but as a final form of the edge-emitting semiconductor laser device, a form formed on the substrate and a form in which the substrate is removed. Can be mentioned. The edge-emitting semiconductor laser element may be mounted (mounted) by a junction-up method or may be mounted (mounted) by a junction-down method. As a method for removing the substrate, a method of removing the substrate by etching after supporting the light emitting portion of the edge-emitting semiconductor laser element with an appropriate support member, a method of removing by polishing, and a combination of etching and polishing are used. And a method of peeling the substrate by causing laser abrasion by irradiating the substrate with laser light from the back surface.

In the present invention, an edge-emitting semiconductor laser device is first provided on a substrate. As such a substrate, a GaAs substrate, an AlN substrate, an InN substrate, a GaN substrate, an AlGaInN substrate, an AlGaN substrate, an AlInN substrate, a GaInN substrate, a sapphire substrate, A SiC substrate, an alumina substrate, a ZnO substrate, a LiMgO substrate, a LiGaO ₂ substrate, a MgAl ₂ O ₄ substrate, a Si substrate, a Ge substrate, and those having a buffer layer formed on the surface (main surface) of these substrates can be mentioned. .

  In the present invention, as compound semiconductors constituting the first compound semiconductor layer, the active layer, and the second compound semiconductor layer, GaN-based compound semiconductors (including AlGaN mixed crystals, AlGaInN mixed crystals, GaInN mixed crystals), InN-based compound semiconductors, An AlN-based compound semiconductor can be exemplified. Examples of n-type impurities added to the compound semiconductor layer include silicon (Si), selenium (Se), germanium (Ge), tin (Sn), carbon (C), and titanium (Ti). Examples of p-type impurities include zinc (Zn), magnesium (Mg), beryllium (Be), cadmium (Cd), calcium (Ca), barium (Ba), and oxygen (O). The active layer may be composed of a single compound semiconductor layer, or may have a single quantum well structure [QW structure] or a multiple quantum well structure [MQW structure]. As a method for forming various compound semiconductor layers including an active layer (crystal growth method, film formation method), metal organic chemical vapor deposition (MOCVD method, MOVPE method), metal organic molecular beam epitaxy method (MOMBE method), halogen Hydride vapor phase epitaxy method (HVPE method) in which can contribute to transport or reaction.

  In the present invention, the light emitting part is provided on the main surface side of the substrate. And it can be set as the structure where the 1st electrode is provided in the back surface of the board | substrate on the opposite side to a main surface, and the 2nd electrode is provided in the top surface of the light emission part. Alternatively, a part of the first compound semiconductor layer or the like is exposed, the first electrode is provided on the exposed part of the first compound semiconductor layer or the like, and the second electrode is provided on the top surface of the light emitting unit. It can be a structure.

  Here, examples of the p-side electrode connected to the p-type compound semiconductor layer include Au / Pt / Pd, Au / Pt / Ti, and Au / Ni. Examples of the n-side electrode connected to the n-type compound semiconductor layer include Au / Pt / Al / Ti, Au / Ti, and Au / Pt / Ti. The material layer listed at the back of “/” is in contact with the compound semiconductor layer and the substrate.

  Further, for the extension part of the n-side electrode and the p-side electrode, for example, [adhesive layer (Ti layer, Cr layer, etc.)] / [Barrier metal] such as Ti layer / Pt layer / Au layer, etc. Layer (Pt layer, Ni layer, TiW layer, Mo layer, etc.) / [Contact part (pad) composed of a multilayer metal layer having a laminated structure such as a metal layer (for example, Au layer) that is compatible with mounting. Part) may be provided. For example, the n-side electrode including the extended portion, the p-side electrode including the extended portion, and the contact portion (pad portion) may be formed by various PVD methods such as vacuum deposition and sputtering, and various chemical vapor deposition methods ( (CVD method) and plating method.

  In the edge-emitting semiconductor laser device of the present invention, the second compound semiconductor layer is provided with recesses on both sides of the current injection region, away from the current injection region, and away from the light emitting end surface. Yes. Therefore, it is possible to reduce the strain and relieve the tensile stress in the active layer portion located in the region away from the light emitting end face of the edge emitting semiconductor laser device. It is possible to reliably prevent the occurrence of problems such as sudden deterioration.

  Hereinafter, the present invention will be described based on examples with reference to the drawings.

  Example 1 relates to an edge-emitting semiconductor laser device (hereinafter abbreviated as a semiconductor laser device) of the present invention.

  1A and 1B are schematic partial sectional views, and FIG. 2 is a schematic plan view, the semiconductor laser device of Example 1 includes a first compound semiconductor layer 21, The active layer 23 and the second compound semiconductor layer 22 are each composed of a laminated structure that is sequentially laminated, and has a light emitting unit 20 that emits laser light from the light emitting end face 26. The second compound semiconductor layer 22 has a stripe-shaped current injection region 31, and the second compound semiconductor layer 22 is on both sides of the current injection region 31 and is separated from the current injection region 31. In addition, a recess 33 is provided in a region 32 away from the light emitting end face 26. In Example 1, the first compound semiconductor layer 21 is an n-type compound semiconductor layer, and the second compound semiconductor layer 22 is a p-type compound semiconductor layer. 1A is a schematic partial cross-sectional view taken along the arrow AA in FIG. 2, and FIG. 1B is a schematic view taken along the arrow BB in FIG. FIG. In FIG. 2, in order to clearly show the recess, the recess is hatched.

  In the semiconductor laser device of Example 1, the light emitting unit 20 has a double ridge structure. That is, the second compound semiconductor layer 22 includes a lower layer portion 22D and three upper layer portions 22A, 22B, and 22C protruding from the lower layer portion 22D. The second upper layer portion 22B of the second compound semiconductor layer located at the center corresponds to the current injection region 31. The concave portion 33 is formed on the second compound semiconductor layer located between the first upper layer portion 22A of the second compound semiconductor layer located at one edge and the second upper layer portion 22B of the second compound semiconductor layer. The second compound semiconductor located between the portion of the lower layer portion 22D and the third upper layer portion 22C of the second compound semiconductor layer located at the other edge and the second upper layer portion 22B of the second compound semiconductor layer It is provided in the lower layer portion 22D of the layer.

A recess 33 is provided in a region 0.2 mm away from the light emitting end face 26. That is, the distance from the light emitting end surface 26 to one end 33A of the concave portion 33 (the end portion of the concave portion located near the light emitting end surface) is DS ₁ (unit: mm), and the other end 33B of the concave portion 33 from the light emitting end surface 26 is. When the distance to (the end of the recess located far from the light emitting end face) is DS ₂ (unit: mm),
0.001 ≦ DS ₁ <0.2
0.2 <DS ₂
Is satisfied. Specifically, when the length of the recess 33 is Lg (= DS ₂ −DS ₁ ),
DS ₁ = 0.001 mm
DS ₂ = 0.031 mm
Lg = 0.030mm
It is.

Further, in the semiconductor laser device of Example 1, as shown in FIG. 1A and FIG. 2, the average width of the recess 33 is W, and the average distance from the current injection region 31 to the recess 33 (unit: mm) is DS ₃ and the length of the active layer 23 is L _Act .
DS ₃ = 0.0015mm
Lg / L _Act = 0.075
It is. In addition, although the recessed part 33 has reached the 1st compound semiconductor layer 21, this is an illustration. The position of the bottom part of the recessed part 33 can be changed suitably.

  Hereinafter, with reference to FIGS. 3A and 3B and FIGS. 4A and 4B which are schematic partial cross-sectional views of a substrate and the like, a method for manufacturing a semiconductor laser device of Example 1 will be described below. Will be explained.

In the following examples, when various compound semiconductor layers are grown by MOCVD, for example, ammonia gas is used as a nitrogen source, and trimethyl gallium (TMG) gas or triethyl gallium (TEG) gas is used as a gallium source. Using trimethylaluminum (TMA) gas as the aluminum source, using trimethylindium (TMI) gas as the In source, using monosilane gas (SiH ₄ gas) as the silicon source, and using cyclopentadienylmagnesium gas as the Mg source Good.

[Step-100]
First, a substrate 10 made of an n-type GaN substrate is carried into an MOCVD apparatus, subjected to thermal cleaning at a high temperature, then the substrate 10 is heated to about 1000 ° C., and then Si-doped GaN (GaN: The buffer layer 11 made of Si) is crystal-grown. Subsequently, the first cladding layer 21 ₁ made of an n-type AlGaN layer and the first guide layer 21 ₂ made of an n-type GaN layer to which silicon (Si) is added as an n-type impurity are successively crystal-grown. Thus, the first compound semiconductor layer 21 can be obtained. Thereafter, an active layer 23 having a multiple quantum well structure composed of a well layer made of InGaN and a barrier layer made of InGaN (however, the composition is different from the well layer) is crystal-grown on the first compound semiconductor layer 21 Let Here, the emission wavelength λ is 400 nm. Thereafter, on the active layer 23, an electron blocking layer 22 ₃ made of Mg-doped Al _0.2 Ga _0.8 N and having a thickness of 10 nm, and a second guide layer 22 made of p-type GaN doped with magnesium (Mg) as a p-type impurity. ₂ and a second clad layer 22 ₁ composed of a p-type AlGaN layer to which magnesium (Mg) is added as a p-type impurity are successively grown to obtain a second compound semiconductor layer 22, and then p-type The second contact layer 25 made of a p-type GaN layer to which magnesium (Mg) is added as an impurity is crystal-grown.

[Step-110]
Thereafter, a mask layer 27 made of SiO _{2 is formed} on the second contact layer 25 by the CVD method, and then annealed in a nitrogen gas atmosphere to activate the p-type impurity (p-type dopant). I do.

[Step-120]
Next, an opening 27A is formed in the mask layer 27 based on the lithography technique and the etching technique, and the second contact layer 25 is exposed (see FIG. 3A). Then, using the mask layer 27 as an etching layer mask, the second contact layer 25 is etched by the RIE method, and the second compound semiconductor layer 22 is partially etched in the thickness direction to form the ridge shape 34. Provided (see FIG. 3B).

[Step-130]
Thereafter, a mask layer 28 made of a resist material is formed based on the lithography technique (see FIG. 4A). The mask layer 28 is provided with an opening 28A for providing a recess. Then, using this mask layer 28 as an etching mask, the second compound semiconductor layer 22, the active layer 23, and further a part of the first compound semiconductor layer 21 in the thickness direction are etched by the RIE method. After the recess 33 is formed, the mask layer 28 is removed by an ashing method, and the mask layer 27 is further removed by a wet etching method. In this way, the structure shown in FIG. 4B can be obtained.

[Step-140]
Next, in the same manner as a normal semiconductor laser device wafer process and chip forming process, a protective film (not shown) is formed, a photolithography process and an etching process, the first electrode 41 is formed on the back surface of the substrate 10 by metal deposition, The second electrode 42 is formed on the top surface of the second compound semiconductor layer 22 (specifically, on the second contact layer 25), and further formed into a chip by cleavage treatment and dicing, and the resin mold, package By performing the process, the semiconductor laser device of Example 1 can be manufactured.

  The semiconductor laser element of Example 1 was subjected to a high output aging test in an atmosphere at 80 ° C. Here, it was driven so that the light output from the semiconductor laser element was 300 milliwatts. As a result, no change in light output was observed even after 100 hours had passed since the start of the aging test. On the other hand, as Comparative Example 1, a semiconductor laser device having the same structure and configuration as Example 1 was prepared except that no recess was provided, and the same aging test was performed. As a result, 10 hours passed from the start of the aging test. At that time, a decrease in light output was observed.

  Thus, in the semiconductor laser device of Example 1, the recess 33 is provided. As a result, it is possible to reduce the strain in the active layer 23 located in a region away from the light emitting end face 26 of the semiconductor laser device, and as a result, the light output is suddenly deteriorated even in the operation at a high output. Can be reliably prevented.

  The second embodiment is a modification of the first embodiment. In the semiconductor laser device of Example 1, the light emitting unit 20 has a double ridge structure. On the other hand, in the semiconductor laser device of Example 2, the light emitting portion 20 has a ridge structure as shown in the schematic partial cross-sectional views of FIGS. That is, in the semiconductor laser device of Example 2, the second compound semiconductor layer 122 has a lower layer portion 122D and an upper layer portion 122U protruding from the lower layer portion 122D. The upper layer portion 122U of the second compound semiconductor layer 122 corresponds to the current injection region 31, and the recess 33 reaches the first compound semiconductor layer 21. 5A is a schematic partial cross-sectional view similar to that taken along the arrow AA in FIG. 2, and FIG. 5B is taken along the arrow BB in FIG. It is the same typical partial sectional view.

  Except for this point, the configuration and structure of the semiconductor laser device of the second embodiment can be the same as the configuration and structure of the semiconductor laser device of the first embodiment. Further, since the semiconductor laser element of Example 2 can be manufactured by substantially the same manufacturing method as that of the semiconductor laser element of Example 1, detailed description thereof is omitted.

  As mentioned above, although this invention was demonstrated based on the preferable Example, this invention is not limited to these Examples. The configuration, structure, structure of the light emitting section, structure, material constituting the edge emitting semiconductor laser element, manufacturing conditions for the edge emitting semiconductor laser element, etc. described in the embodiments are examples, Can be changed. For example, in the edge-emitting semiconductor laser element described in the embodiment, the final form of the edge-emitting semiconductor laser element is described as being formed on the substrate. Alternatively, the substrate is polished or etched. Alternatively, the first electrode 41 may be formed on the exposed compound semiconductor layer.

  In some cases, a semiconductor laser element having a mesa structure may be used. Specifically, for example, in the semiconductor laser device of Example 2, a sapphire substrate is used as the substrate 10 ′. In [Step-140], the second contact layer 25, the second compound semiconductor layer 22, the active layer 23, Then, a part of the first contact layer 24 is exposed by etching a part of the first compound semiconductor layer 21 and the first contact layer 24. Then, the first electrode 41 is formed on the exposed portion of the first contact layer 24, and the second electrode 42 is formed on the top surface of the second compound semiconductor layer 22 (specifically, on the second contact layer 25). To do. In this way, a semiconductor laser device having a structure shown in a schematic partial cross-sectional view in FIG. 6A can be obtained.

  6B, the second compound semiconductor layer 222 has a lower layer portion 222D and an upper layer portion 222U, and the upper layer portion 222U includes the current injection region 31 and Alternatively, the current injection region may be configured by a region 35 for constricting current provided on both sides of the current injection region. In this case, a recess 33 is provided in the region 35 where current is confined. Here, the region 35 for confining current can be obtained, for example, by implanting boron ions or hydrogen ions and making the ion-implanted region a high resistance region or an insulating region.

  Various modifications of the planar shape of the concave portion 33 are schematically illustrated in FIGS. 7A to 7Z, but the planar shape of the concave portion can be essentially any shape. In FIGS. 7A to 7Z, in order to clarify the upper layer portion and the concave portion of the second compound semiconductor layer, the upper layer portion of the second compound semiconductor layer in the double ridge structure is changed from the upper right to the lower left. The hatching which goes is attached, and the hatching which goes from the upper left to the lower right is attached to the concave portion.

1A and 1B are schematic partial cross-sectional views of the edge-emitting semiconductor laser device of Example 1 along arrows AA and BB in FIG. 2, respectively. . FIG. 2 is a schematic partial plan view of the edge-emitting semiconductor laser device according to the first embodiment. 3A and 3B are schematic partial cross-sectional views of a substrate and the like for explaining the method for manufacturing the edge-emitting semiconductor laser device of Example 1. FIG. 4A and 4B are schematic partial cross-sectional views of a substrate and the like for explaining the manufacturing method of the edge-emitting semiconductor laser device of Example 1, following FIG. 3B. is there. FIGS. 5A and 5B are schematic partial cross-sectional views of the edge-emitting semiconductor laser device of Example 2, similar to those taken along arrows AA and BB in FIG. It is. 6A and 6B are schematic partial cross-sectional views of modifications of the edge-emitting semiconductor laser device of the present invention. (A)-(Z) of FIG. 7 is a top view which shows typically the various modifications of the planar shape of a recessed part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 11 ... Buffer layer, 20 ... Light emission part, 21 ... 1st compound semiconductor layer, 21 ₁ ... n-type clad layer, 21 ₂ ... n-type guide layer, 122 ... second compound semiconductor layer, 22 ₁ ... p-type cladding layer, 22 ₂ ... p-type guide layer, 22 ₃ ... electron block layer, 22A, 22B, 22C, 122U, 222U ... -Upper part of the second compound semiconductor layer, 22D, 122D, 222D ... Lower part of the second compound semiconductor layer, 23 ... Active layer, 24 ... First contact layer, 25 ... Second contact Layer, 26... Light emitting end face, 27, 28... Mask layer, 27A, 28A... Opening provided in mask layer, 31... Current injection region, 32. Layer region, 33 ... recess, 33A ... one end of recess, 33B ... The other end of the recess, 34... Ridge shape, 35... A region for confining current provided on both sides of the current injection region, 41... The first electrode (n-side electrode), 42. 2 electrodes (p-side electrode)

Claims (5)

The first compound semiconductor layer, the active layer, and the second compound semiconductor layer are each composed of a laminated structure that is sequentially laminated, and has a light emitting portion that emits laser light from a light emission end face.
The second compound semiconductor layer has a stripe-shaped current injection region, and
An edge-emitting semiconductor laser device in which the second compound semiconductor layer is provided with recesses on both sides of the current injection region, spaced from the current injection region, and in a region away from the light emitting end surface. The second compound semiconductor layer has a lower layer portion and an upper layer portion protruding from the lower layer portion,
The upper layer portion of the second compound semiconductor layer corresponds to the current injection region,
The edge emitting semiconductor laser device according to claim 1, wherein the recess is provided in a lower layer portion of the second compound semiconductor layer. The second compound semiconductor layer has a lower layer portion and three upper layer portions protruding from the lower layer portion,
The second upper layer portion of the second compound semiconductor layer located in the center corresponds to the current injection region,
The concave portion is a portion of the lower layer portion of the second compound semiconductor layer located between the first upper layer portion of the second compound semiconductor layer located on one edge and the second upper layer portion of the second compound semiconductor layer, And provided in the lower layer portion of the second compound semiconductor layer located between the third upper layer portion of the second compound semiconductor layer located at the other edge and the second upper layer portion of the second compound semiconductor layer. The edge-emitting semiconductor laser device according to claim 1.   2. The edge-emitting semiconductor laser device according to claim 1, wherein the recess is included in a region separated by 0.2 mm from the light emitting end face. 5. The edge-emitting semiconductor laser device according to claim 4, wherein the length of the recess is 1 × 10 ⁻⁶ m or more.

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